libjnr-ffi-java binary package in Ubuntu Focal amd64

 Java Native Runtime (JNR) is a collection of Java libraries to make
 interfacing with OS-level features easier. JNR uses an alternate
 method to JNI or JNA to achieve programming simplicity while still
 retaining performance.
 .
 The jnr-ffi package is a set of abstractions that build on the lower-level
 libraries implemented by the jffi package. jnr-ffi allows one to load
 native libraries without writing JNI code by hand, or using tools
 such as SWIG.

Source package